Johnston Atoll
- ISS002-E-8829
- 11 July 2001
- 01:00 UTC
Johnston Atoll is one of the most isolated atolls in the world, located in the north Central Pacific, some 1,325 km south west of Honolulu; the nearest lands to Johnston Atoll are the tiny islets of the French Frigate Shoals, around 800 km to the north east, in the Northwestern Hawaiian Islands, (see panoramic image).
Johnston Atoll — an unincorporated territory of the USA — consists of a shallow coral reef platform extending over about 130 km². The lagoon is not protected by an encircling reef crest, but has a reef along its northwest margin, protecting a shallow lagoon of 11 km by 3 km from the predominant waves from the northwest. Depths in the lagoon vary from about 3 to 10 m. The atoll is not enclosed because the platform on which it sits has subsided and is tilting to the southeast. Most of the reef platform lies outside of the lagoon, extending about 19 km east-southeast and 8 km south of Johnston Island.
There are four islands on the atoll: Johnston Island, Sand Island, Akau (North Island), and Hikina (East Island), with a total land area of 2.8 km². Both Akau and Hikina are artificial islands created by coral dredging and filling. As well as creating two new islands, the original two islands of the atoll have also been greatly enlarged: Johnston Island from 0.19 km² to 2.3 km² and Sand Island from 0.04 km² to 0.16 km². In all, the land area at Johnston Atoll has been increased artificially nearly 10-fold. [In the image large areas where dredging has taken place can be seen as deeper areas of water around the largest island.] Most dredging took place after WWII and in the 1960's as military facilities on the atoll were expanded.
Formerly used as a refueling site for aircraft and submarines during WWII and as a base for airlift operations during the Korean War, and later as a site for nuclear weapons tests, chemical weapons storage and recently as a chemical weapons destruction facility, Johnston Atoll was handed over to the US Fish and Wildlife Service in 2003 to manage the atoll as part of the Hawaiian and Pacific/Remote Islands National Wildlife Refuges system.
The area is a habitat for seabirds and shorebirds. The reef community in the lagoon supports diverse marine life including the threatened Green Turtle.
